The method that best worked for me does not require to clone the repo.

I found the answer in this SO post, who took it from Chris Herron @ Sourcecon:

• Browse someone's commit history (Click commits which is next to branch to see the whole commit history)

• Click the commit that with the person's username because there might be so many of them

• Then you should see the web address has a hash concatenated to the URL. Add .patch to this commit URL

• You will probably see the person's email address there

Example: https://github.com/[username]/[reponame]/commit/[hash].patch